Dump trucks or so-called large dump trucks are predominantly used in coal mining operations or ore mining operations for the transport of the mined coal, minerals and ores. These bulk material dumpers are manufactured in sizes of more than 90 metric tons (t) up to several 100 t in weight and payload so that they have very large dimensions overall.
A diesel electric drive is used as the traction drive, wherein the mechanical energy generated by a diesel engine is converted with the aid of an alternator into electrical energy for the supply of the electric traction drives. The reason for this process is that diesel engines, like all internal combustion engines, can only be operated with ideal efficiency in a very restricted speed range and cannot be started under load. The AC motors for the driving axle can also produce the desired torque in the lower speed range for starting. The internal combustion engine used can be operated continuously in the ideal speed range.
Corresponding power electronics are required for the control of the one or more electric motors and of the alternator. They as a rule include one or more frequency converters to regulate the required speed at the electric motors.
In the known work machines, in particular dump trucks, a large radiator is arranged above the bumper in the part of the work machine at the front in the direction of travel and an upper deck which can be walked on is disposed above it. The operator's cabin is typically arranged laterally above one of the wheels at the level of the upper deck. A switch cabinet which is accessible from the upper deck and which includes the required power electronics for the control or regulation of the alternator and of the driven electric motors is installed next to the operator's cabin on the upper deck. The alternator or the electric motors themselves are, on the other hand, installed in the vehicle frame, with the electric motors optionally being integrated into the driven rear axle and the alternator being mounted in the proximity of the internal combustion engine.
Due to the large dimensions of the work machine, long line paths are necessary to connect the alternator to the power electronics or the power electronics to the electric motors. The required cable harness consequently has to be conducted from the alternator in the vehicle frame for several meters upwardly up to the upper deck of the vehicle and from there back into the vehicle frame to the driven rear axle.
However, the long line paths increase the effort for the cabling. The huge line length furthermore promotes the likelihood of electromagnetic interference, in particular between the power lines and the signal lines for transmitting the control signals to the alternator and to the electric motor.
The object of the present disclosure deals with an alternative design of the diesel electric drive train which can overcome the above-named problems.
This object is achieved by a work machine in particular in the form of a dump truck or of a truck, having a diesel electric traction drive, comprising at least one internal combustion engine, at least one alternator, at least one set of power electronics as well as at least one electric motor. Starting from this, it is proposed in accordance with the present disclosure to arrange the power electronics or at least some of the power electronics in the region of a driven driving axle of the work machine. The work machine may include various of the features of work machines described herein, such as an upper deck, an operator cabin, etc., positioned as described above herein.
A decisive shortening of the required line paths between the power electronics and the electric motor is achieved by the arrangement of the power electronics in the region of the driven driving axle and/or in the region of the electric motors to be supplied with energy. The power electronics are in particular not installed on the upper deck of a mining truck, but instead below the upper deck, such as near the ground in the region of the driven vehicle axle. Not only a service-friendly access to the power electronics hereby results, but the required line paths between the electrical components are also shortened, whereby the likelihood for electromagnetic interference is minimized. In addition, the risk for the operating personnel is further reduced since the power electronics no longer lie in the danger area of the operator's cabin on the upper deck.
The at least one alternator, the power electronics and the at least one electric motor are particularly arranged behind one another at the vehicle in the direction of travel, optionally at the vehicle frame. Not only particularly short line paths thereby result between the electric motor and the power electronics, but also between the alternator and the power electronics. The already above-described advantages of the arrangement in accordance with the present disclosure are further optimized. An installation of the power electronics at least partially between the alternator and the driven driving axle is possible.
The vehicle frame typically comprises at least two frame beams which extend in parallel and which extend at least sectionally in parallel in the longitudinal direction of the vehicle. The power electronics can ideally be mounted between the two frame beams. The installation between the vehicle frame beams provides additional protection for the power electronics. In addition, this installation location is characterized by good service friendliness since the region is easily accessible from the ground and no other components of the work machine block access.
Alternatively, the power electronics can also be installed at least partially at the outside at the vehicle frame, i.e. at the outside at the vehicle beams. It is also conceivable that some of the power electronics are fastened between the vehicle beams and some others are fastened at the outside at at least one vehicle beam. There is the possibility that a respective component of the power electronics is installed both on or at the left vehicle beam and on or at the right vehicle beam.
The power electronics can be integrated in one part within a common housing which is selectively fastenable between the vehicle beams of the vehicle frame or at the outside at one of the vehicle beams. It is also conceivable that the power electronics have a modular design, i.e. the power electronics comprise two or more functional modules each having an encapsulated housing. In this case, a common arrangement in the vehicle frame, i.e. between the vehicle beams or a common arrangement at the outside at the vehicle frame is conceivable. At the same time, an installation of a first functional module in the frame between the frame beams and the fastening of the second or of a further functional module at the outside at the frame are conceivable.
Further numerous installation possibilities for the individual functional modules of the power electronics are naturally conceivable which cannot be exclusively listed here. The gist of the present disclosure, however, comprises the distance of the power electronics, i.e. at least of some of the functional modules, from the alternator and/or from the driven driving axle being dimensioned as short as possible to achieve the advantages in accordance with the present disclosure.
A particular advantage of the technical solution in accordance with the present disclosure results in that the power electronics are easily accessible, optionally with an upwardly tilted skip of the work machine, so that service work, installation work and dismantling work are simplified. During regular operation, the power electronics are protected from external environmental influences, on the one hand, by the skip and, on the other hand, by the vehicle frame. The skip is tilted up for the installation and a simple access from above close to the ground is achieved.
It is conceivable for this purpose that one or more lifting gears are provided at the work machine, in particular in the region of the skip, particularly at the front lower edge of the skip, to be able to take up the power electronics or individual functional modules. A simple installation possibility or dismantling possibility for the power electronics or for individual components of the power electronics can be provided with the aid of the lifting gear. In addition to the vertical lifting movement, the lifting gear can additionally provide a horizontal movement of the load to be able to easily move the taken up functional modules.
Further advantages and properties of the work machine in accordance with the present disclosure result from the embodiments shown in the drawings.